Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
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Article Citation - WoS: 4Citation - Scopus: 4Mesoscale Morphologies of Nafion-Based Blend Membranes by Dissipative Particle Dynamics(MDPI, 2021-06-02) Sen, Unal; Ozdemir, Mehmet; Erkartal, Mustafa; Kaya, Alaattin Metin; Manda, Abdullah A.; Oveisi, Ali Reza; Tokumasu, TakashiPolymer electrolyte membrane (PEM) composed of polymer or polymer blend is a vital element in PEM fuel cell that allows proton transport and serves as a barrier between fuel and oxygen. Understanding the microscopic phase behavior in polymer blends is very crucial to design alternative cost-effective proton-conducting materials. In this study, the mesoscale morphologies of Nafion/poly(1-vinyl-1,2,4-triazole) (Nafion-PVTri) and Nafion/poly(vinyl phosphonic acid) (Nafion-PVPA) blend membranes were studied by dissipative particle dynamics (DPD) simulation technique. Simulation results indicate that both blend membranes can form a phase-separated microstructure due to the different hydrophobic and hydrophilic character of different polymer chains and different segments in the same polymer chain. There is a strong, attractive interaction between the phosphonic acid and sulfonic acid groups and a very strong repulsive interaction between the fluorinated and phosphonic acid groups in the Nafion-PVPA blend membrane. By increasing the PVPA content in the blend membrane, the PVPA clusters' size gradually increases and forms a continuous phase. On the other hand, repulsive interaction between fluorinated and triazole units in the Nafion-PVTri blend is not very strong compared to the Nafion-PVPA blend, which results in different phase behavior in Nafion-PVTri blend membrane. This relatively lower repulsive interaction causes Nafion-PVTri blend membrane to have non-continuous phases regardless of the composition.Article Citation - WoS: 21Citation - Scopus: 21Enhancement of Anhydrous Proton Conductivity of Poly(Vinylphosphonic Acid)-Poly(2,5 Membranes Via in Situ Polymerization(Wiley-VCH Verlag GmbH, 2014-10-16) Sen, Unal; Usta, Hakan; Acar, Oktay; Citir, Murat; Canlier, Ali; Bozkurt, Ayhan; Ata, AliPolymer electrolyte membranes (PEMs) are synthesized via in situ polymerization of vinylphosphonic acid (VPA) within a poly(2,5-benzimidazole) (ABPBI) matrix. The characterization of the membranes is carried out by using Fourier transform infrared (FTIR) spectroscopy for the interpolymer interactions, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) for the thermal properties, and scanning electron microscopy (SEM) for the morphological properties. The physicochemical characterizations suggest the complexation between ABPBI and PVPA and the formation of homogeneous polymer blends. Proton conductivities in the anhydrous state (150 degrees C) measured by using impedance spectroscopy are considerable, at up to 0.001 and 0.002 S cm(-1) for (1: 1) and (1: 2) molar ratios, respectively. These conductivities indicate signifi cant improvements (> 1000x) over the physically blended samples. The results shown here demonstrate the great potential of in situ preparation for the realization of new PEM materials in future high-temperature and non-humidified polymer electrolyte membrane fuel cell (PEMFC) applications.